In world history, post-classical history refers to the period from about 500 CE to about 1450 or 1500 CE, roughly corresponding to the European Middle Ages following the decline of the western Roman Empire. The post-classical period is characterized by the expansion of certain civilizations geographically, by ongoing wars fought over land, resources and religion, and by the development of trade networks between often-distant civilizations. This period is also called—with various implications and emphases—the medieval era, the post-antiquity era, the post-ancient era, or the pre-modern era.